Apparatus for testing a coefficient of friction and methods for same

A method for comparing a coefficient of friction of each of a first article and a second article, wherein the first article is formed of a first material and the second article is formed of a second material that is different from the first material, the method comprising:

• placing the first article on a first travel path defined by a ramp when the ramp is at a first angular position;
• tilting a distal end of the ramp upwardly into a second angular position such that the article begins to slide down the ramp along the first travel path;
• placing the first article on a second travel path defined by the ramp when the ramp is at the first angular position;
• tilting the distal end of the ramp upwardly into a third angular position such that the first article begins to slide down the ramp along the second travel path;
• placing the second article on the first travel path defined by the ramp when the ramp is at the first angular position;
• tilting the distal end of the ramp upwardly into a fourth angular position such that the second article begins to slide down the ramp along the first travel path;
• placing the second article on the second travel path defined by the ramp when the ramp is at the first angular position;
• tilting the distal end of the ramp upwardly into a fifth angular position such that the second article begins to slide down the ramp along the second travel path;
• calculating a first average coefficient of friction for the first article based on the first angular position, the second angular position, and the third angular position;
• and
• calculating a second average coefficient of friction for the second article based on the first angular position, the fourth angular position, and the fifth angular position.

A combination comprising:

• an article comprising a body that defines a first diameter;
• and
• an apparatus for testing a coefficient of friction of the article, the apparatus comprising:
• a base;
• a ramp that comprises a first rail and a second rail that are spaced apart by a first distance and cooperate to define a first travel path for the article;
• and
• an actuator coupled with the base and operably coupled with the ramp to facilitate selective pivoting of the ramp between a first angular position and a second angular position;
• wherein:
• the first diameter is greater than the first distance by a ratio of at least about 4 to about 1;
• and
• the first rail and the second rail cooperate to provide underlying support for the article and to facilitate selective sliding of the article with respect to the ramp along the first travel path.